Kodak Hypo Clearing Agent has been around for decades and was a favourite with the likes of Ansel Adams et al.
Supplied as a powder, this is dissolved as per the instructions to make a stock solution of 3.8L. You then use this stock and dilute 1:4 for use. This product will dramatically speed up and also improve the quality of your film and paper washing, removing residual fixer which, if left in the emulsion, will degrade the film or paper over time, sometimes really quite quickly.
As a basic rule of thumb, when washing film, give an initial rinse after fixing – a couple of tank changes of water at 18–24ºC. Then fill the tank with Hypo Clearing Agent, at roughly 18–24ºC, and agitate continuously for around 2 minutes. Pour out the solution and then give a further 3 or 4 water changes, and in the final one add some wetting agent to the tank (use distilled water for this final tank full if you are in a hard water area).
Note: the colder your wash temperature the slower it is. If washing at cold tap temperature, which is around 10ºC depending on time of year and your supply, wash times would be very long and extremely inefficient. Ansel Adams explores this in detail in his book “The Print”. Wash temperature should not fall below 18ºC as efficiency falls away very quickly below this.